Coaxial conductor



Patented Feb. 15, 1949 UNITED STATES PATENT QFFICE coaxial. CONDUCTOR Louis n. Morin, Bronx, N. Y. Application February 26, 1944, Serial No. 524,122

1 Claim. l

This invention relates to electric conductors generally classified as coaxial conductors or cable wherein an insulator is employed to support and space an inner conductor from an outer conductor, and in providing an air space between said conductors. More particularly, the invention relates to a product of manufacture comprising a conductor strand of any desired cross sectional form upon which is directly cast a spiral or helix insulator member in forming said product. Still further, the invention comprises forming the spiral or helix of such cross sectional form as to satisfy different requirements in products of the kind under consideration. The novel features-of the invention will be best understood from the following description when taken together with the accompanying drawing, in which the separate parts are designated by suitable reference characters in each of the views; and in which:

Fig. 1 is a longitudinal sectional view diagrammatically illustrating one form of conductor made according to my invention, showing the conductor in a partially flexed position.

Fig. 2 is a section on the line 2-2 of Fig. l.

Fig. 3 is a detail side view of an insulated conductor product, showing a modified construction.

Fig. 4 is a section on the line 4*@ of Fig. 3.

Fig. 5 is a View similar to Fig. 3, showing another adaptation of my invention; and

Figs. 6 and 7 are longitudinal sectional views of other conductor products, showing further modications.

The use of insulating mediums of the general type and kind forming the subject matter of the present invention are known. However, in such known uses, the insulator has comprised a separate product of manufacture which after fabrication has then been applied or attached to a conductor 'oy winding, twisting or in any other fashion.

i My invention comprises the formation of a product comprising the conductor and they insulator as a unit .part thereof. Tin other words, in forming the insulator, it is -formed upon and as part of the conductor, and is securely united or fixed thereto by the natural properties or characteristics of die casting the insulator upon the conductor strand.

As the use and advantages of coaxial cable of the type and kind under consideration are well known to those skilled in the art, no specific characteristics or advantages of the resulting product will here be dealt with, except insofar as the several forms of my improved conductor product may contribute advantageously to the perfection and use of coaxial cable or conductors of the kind under consideration.

To illustrate one adaptation and use of the invention. I have diagrammatically illustrated in Figs. l and 2 of the drawing an outer tubular conductor I0, upon which is arranged suitable ins'ulation Il in the form of two or more sheaths.

Within the tubular conductor I0 is arranged one form of my improved insulated conductor products I2. The product l2 comprises a strand like conductor member i3 of any desired cross sectional form, and by this is meant also that the conductor may be solid or tubular, and at i4 is illustrated the insulator part of the product i2.

The insulator part is die cast upon the conductor I3 in the form of a continuous spiral or helix substantially of the cross sectional form seen in Fig. 2 of the drawing. That is to say, the inner end portion I5 of the blade like cross sectional form of the spiral or helix is considerably wider than the outer edge i6 thereof.

The inner end portion l5 substantially adheres to the surface of the conductor i3 contacted thereby as indicated at il, whereas the outer edge'i 6 is adapted to ht'within the inside diameter I8 of the conductor l 0. The particular method and apparatus for producing the insulator conductor product i2 forms the subject matter of companion method and machine applications, Serial No. 532,659, now Patent No. 2,446,057 issued July 27, 1948 and Serial No. 532,660, now Patent No. 2,456,304 issued December 14, 1948.

The insulator part of the several products hercin illustrated will all be formed of suitable insulating material, such for example, as cellulose acetate, or other plastic materials which can' be die cast or molded to produce products of the kind defined.

With the construction shown in Figs. i and 2 of the drawing, a rather wide or extended spiral or helix is employed. in some instances, this is advantageous from the standpoint of producing the wide spaces between, for example, the points i9 and 20 of Fig. 1, which provides for a freer bending or flexure of the cable or conductor as partially illustrated at the lower portion of Fig. l. Furthermore, Aa greater amount of air'space is provided, and this space extends itself longitu dlnally to a great extent by reason of the open spiral or helix to encourage circulation or distri bution of air as and vwhen this would be an advantageous factor.

In Figs. 3 and 4 of the drawing 4I have illustrated a slight modiilcation of the structure shown in Figs. 1 and 2. This modification comprises an insulated conductor product 2 I comprising a conductor part`22 and an insulator part 23. The part 23 is generally of the same structure as the part I4, being modied solely in the provision of added rings or sleeves 24, completely enveloping the conductor part 22 at longitudinally spaced intervals, substantially in the manner illustrated in Fig. 3. 'Ihe rings or sleeves form reinforcing or binder members, which will reinforce the attachment of the insulator part 23 with the conductor part 22, and vwill be formed of the same insulating material as employed in the part 23 and die cast on the part 22 in the process of casting the part 23 thereon. In other words, the rings or sleeves 24 are integral portions of the part 23.

In Fig. of the drawing I have shown at 25, an insulated conductor product comprising a conductor part 26 and an insulator part 21. In this construction the part 21 comprises a spiral or helical ribbon like portion 28, and centrally of the ribbon portion is a radially extending web portion 29, the latter being substantially similar to the parts I4 and 23 of Figs. 1 and 3. Another manner of describing the structure of Fig. 5, would be in saying that the portion 29 of the insulator part 21 is similar to the parts I4 and 23,

and that this part has the ribbon like inner surface or laterally extending flanges 30 on the inner surface thereof, which forms the ribbon like portion 28.

The structure of Fig. 5 enlarges upon the contact area of the insulator part with the conductor part, and instead of increasing these contact areas by small rings or sleeves, as in Fig. 3, the

wide ribbon like portions are employed. With this construction substantially half or possibly a little more than half of the conductor part 26 will be covered. In some uses or adaptations of the invention, this would be an advantageous feature. On the other hand, in some instances, it would be desirable to reverse the procedure and establish a lesser engagement of the insulator part with the conductor part, and a greater outer contact-surface of the insulator with the outer conductor similar to the conductor I0, as forl example in Fig. '1 of the drawing.

In Fig. 7,' the insulator conductor product comprises a conductor part 3i and a spiral or helix insulator part 3,2.v The coils of the part 32 are substantially triangular in cross-sectionall form with one side surface 33 of the triangular section forming the outersurface of the part 32, and the other surfaces of the triangular section contracting to an inner substantially pointed end 3Q, which is secured 'to the part 3l.Y With this construction, as seen in Fig. 'l of the drawing, the coils of the spiral or helix are closely arranged, thus forming relatively narrow spaces 35 between adjacent coils. These spaces will be suilicient to provide the desired flexure in the resulting cable or conductor. However, the air space will be materially cut down, as compared with the devices shown in Figs. 1, 3 and 5 of the drawing, andY yet a complete spiral or helical air passage will be produced throughout the length ofthe conductor part 3l.

In Fig. 6 of the drawing is shown another` adaptation of the invention which modii-les the structures of Figs.A 5 and 7, and combine certain features of each of these two structures. In Fig,

6, the insulated conductor product comprises a 4 than the ribbon part 28, and having a radial web 33 extending outwardly from one side edge of the ribbon part 38, the web 39 terminating in a wide flange extension 40, which forms the outer surface of the part 31, substantially similar to the surface 33. The flange portion 4|! will naturally form on the resulting part 31 what would appear to be a spiral or helical flat spring like structure extending longitudinally of the conductor part 36 and spaced therefrom by the web 33. With the structure of Fig. 6, a maximum contact will be established with the outer conductor, that is to say, a conductor similar to the conductor III, and

a medium mounting or support on the conductor part v36 is provided by reason ofthe narrow ribbon 38. This contact will be substantially the same as the contact of the insulator I4 with the conductor I3, except that the ribbon 38 is more closely positioned longitudinally ofthe conductor part'36. In this connection, it will be understood that with the construction of Fig. 6 as w ell as the structure of Fig. '7, a wider spacing of the coils may be provided in different adaptations and uses of the respective products.

Various conductor products ofthe kind illustrated comprising the conductor part with the insulator part thereon and as a unit part thereof,

will be sold in the required lengths for use in the production of coaxial cable or conductors of the general type and kind illustrated diagrammetically in Figs. 1 and 2 of the drawing, or the insulators may be cast on the conductor just prior to the application of the outer conductor and insulator and insulators thereon, in forming the nal product.

- It will be apparent that in cutting oi lengths of the insulated conductor products,` it will be immaterial where the product is cut, asat all times, adhesion is established between the conductor part and insulator part throughout the full length of the product. This adhesion or secure relationship between the two parts of the product is not only desirable from the standpoint of handling the product, but also from the standpoint of maintaining proper' relationship and I centralization of the conductor part within the or conductor.

axial portion -of Athe .outer tubular conductor in producing coaxial cables or conductors, and particularly in substantially maintaining this central relationship in the ilexing'or bending of the cable It will also be understood that many plastic materials which may be employed in forming the insulator parts of the product have natural'exing properties or characteristics which will vadapt them to the uses here intended.

Coaxial cableA or conductors of the kind under consideration are adaptable for use in Very high frequencies as well as in low frequencies. In some instances, the plastic material employed in forming the 'insulator may be polyethylene, a product having high dielectric properties. However, in other instances, many of the other types and kinds of plastics may be employed. particularly of the kind that may be molded or die cast directly upon the conductor so as to become an integral part thereof.

By casting the insulator directly upon the conductor, positive control of centralization of the conductor in the outer tubular conductor is maintained. 'It will also appear .that the more or less helical' line contact of the insulator with the conductor as disclosed in Fig. 'I is particularly desirable in certain radio uses of cable or conductor, and particularly in antenna tuning.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

In coaxial cable, an electric conductor, a helix member of insulating material arranged upon and extending longitudinally of said conductor, said member having a ribbon portion in contact with the conductor and an annular ilange spaced from said portion and forming a wide helical surface portion substantially paralleling the longitudinal axis of the conductor, and a web extending radially and perpendicularly to said ribbon portion and integral with said ribbon portion and iiange, the width of the ribbon portion being greater than the thickness of the web but less than the width of the flange.

LOUIS H. MORIN.

REFERENCES crran The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,597,422 Bassett Aug. 24, 1926 1,955,468 Noyes Apr. 17, 1934 2,035,274 Mougey Mar. 24, 1936 2,204,737 Swallow June 18, 1940 2,288,900 Gits July 7, 1942 FOREIGN PATENTS Number Country Date 18,725 Great Britain, 1895 Aug. 22, 1896 137,968 Austria June 11, 1934 447,742 Germany July 23, 1927 452,779 Great Britain Aug. 27. 1936 

